<!DOCTYPE html>
<html lang="en">
        <meta charset="UTF-8">
<head>
    <title>Document</title>
</head>
<body>
    <div>我是一个粉刷匠</div>
    <div>我是一个粉刷匠</div>
    <div>我是一个粉刷匠</div>
    <div>我是一个粉刷匠</div>
    <div>我是一个粉刷匠</div>
    <script>
    (function(window,undefined) {
        var jQuery = function(selector) {
            return new jQuery.fn.init(selector);
        }
        //原型替换
        jQuery.fn = jQuery.prototype = {
            constructor: jQuery,
            init: function(selector) {
               var elements = document.querySelectorAll(selector);
               [].push.apply(this,elements);
            },
            css: function() {
                console.log("css is big")
            }
        }
        window.jQuery = window.$ = jQuery 
    })(window)
    var $divs = $("div")
    console.log($divs)
    // $divs.css()
    
    
    
    </script>
</body>
</html>